At the outset of nuclear talks between Iran and the 5+1 Powers two weeks ago, we explained in a 5-point guide, “Why a Nuclear Deal May Not Happen — 5 Points & 1 Word (‘Centrifuges’)”:

unless both sides come off their fixed views on centrifuges, disillusionment, suspicion, and hostility will be added to the mix of crises — including Iraq and Syria — that are already promising a less-than-stable future for both Washington and Tehran.

See Iran Special: Why a Nuclear Deal May Not Happen — 5 Points & 1 Word (“Centrifuges”)

While our gloomy prediction has been mitigated by the imminent agreement to extend an interim nuclear agreement, allowing talks to continue into the autumn, the basic warning remains: Iran and the 5+1 are still far apart on how many centrifuges — and the development of those centrifuges — that Iran can operate for enrichment of uranium in its civilian nuclear program.

The Islamic Republic insists that it must expand its stock of 19,000 centrifuges and/or introduce advanced models for far more efficient production of enriched uranium. The US and European allies not only are dismissing expansion; they are demanding a reduction in the number — and they refuse to countenance operation of models beyond the 40-year-old IR-1 centrifuges.

That much has been reported by international media covering the talks. What has been missed is the shift in the talks, taking them from behind closed doors, and the issue beyond centrifuges: a little-known, little-understood concept of “Separative Work Units”.

To explain, we hand over to the Supreme Leader of Iran, Ayatollah Ali Khamenei….


On July 7, soon after the resumption of talks, the Supreme Leader gave a high-profile statement of support for the Rouhani Government’s pursuit of an agreement.

However, the speech was more important for a detail that escaped the notice of reporters outside Iran.

For the first time, Ayatollah Khamenei set out a specific demand for the outcome of the talks, beyond recognition of Iran’s right to enrichment, maintenance of its nuclear facilities, and the lifting of US-led sanctions.

Khamenei said that, within a period of several years, Iran must have the capability for output of 190,000 “Separative Work Units” from its centrifuges.

Iranian officials say that is the minimum amount necessary to fuel the Bushehr nuclear reactor, built by Russia and put into operation in 2013. While the Russians are contracted to provide uranium for Bushehr until 2021, Tehran — which has not had the happiest of relations with Moscow over contracts and the nuclar program in the past — wants to ensure self-sufficiency.

With his statement, the Supreme Leader not only broke the agreement between Iran and the 5+1 Powers to maintain secrecy in the talks. He was explaining that the key issue is not just the number of centrifuges — the marker used in almost all reports on the talks.

Just as important are the questions of whether Iran can put IR-2m centrifuges, introduced into enrichment plants in January 2013, into operation and whether it can develop the even more advance IR-4 model.


The centrifuge is only a vessel for enrichment of uranium. The marker of output is the “Work Unit”, how much enriched uranium a single centrifuge can produce.

An IR-1 centrifuge produces about 1 Separative Work Unit. An IR-4 centrifuge is projected by Iranian officials to produce about 20 Work Units.

Right now, Iran has about 10,000 operating IR-1 centrifuges, or about 10,000 Separative Work Units.

The simple but misleading presentation of Iran’s demands — one spread by Western media in mis-translations of the Supreme Leader’s speech — is that Iran is insisting on 190,000 centrifuges.

It’s not, as the Supreme Leader’s emphasis on “Work Units” should have made evident.

Instead, high-level Iranian officials clarified that Iran can accept an endpoint of the current level of 10,000 centrifuges, provided those centrifuges are advanced models.

The equation? 10,000 IR-4 centrifuges x 20 Work Units = 200,000 SWUs — more than enough for Bushehr.


The Iranians also have offered what they see as a working compromise for the introduction of the advanced centrifuges.

In his speech, the Supreme Leader set his target of 190,000 SWUs within several years, implying that an increase did not have to be immediate.

Foreign Minister Mohammad Javad Zarif reiterated the point this week when he spoke to Western outlets of a “freeze” in the current level of enrichment, provided that agreement was also reached on a timetable for Iran to reach its goal of self-sufficiency for Bushehr.

Unfortunately, accounts of Zarif’s statement — notably in The New York Times — were garbled, meaning that almost no one understood the “innovative proposal” over Work Units and centrifuges.


Not right now, and that is why the Vienna talks will adjourn on Friday without an agreement.

If asked about Work Units, US and British officials have been dismissive, maintaining that it does not alter the central issue of centrifuges.

That is an evasion which hides the double block of the West on Iranian demands: 1) You cannot have more centrifuges and 2) You cannot have advanced models.

And they have been no more receptive — at least publicly — to the Iranian suggestion of a phase-in of the additional capacity. No consideration has been allowed for Iranian development in one year, two years, or five years.

Instead, the Western officials put up the barrier that any comprehensive nuclear agreement will have to be 10-15 years in duration, implying that Iranian expansion can only be countenanced after that distant point.


Both sides are holding to the notion of an agreement, thus the agreement for an extension of the interim deal to allow more discussions.

But it’s hard to see a compromise between an Iranian endpoint of a 19-fold expansion in its capacity for enrichment and a US-European position of reduction.

The Iranian vision is that the “freeze” period, maintain current capacity, will allow for the building of goodwill. See how we keep to the agreement in Year 1 and in Year 2 we can begin the introduction and development of the newer models. By the time the Russian contract for Bushehr ends in 2021, the West will be assured of no Iranian military nuclear program and Tehran can have self-sufficiency.

But the US-European position is not based on goodwill. It’s based on suspicion: we don’t believe that Iran has completely ruled out a military program in the future, so Tehran cannot have the capacity for any “break-out” possibility within months. An agreement has to preclude that possibility — in other words, the Work Units from advanced models — for more than a decade.

Because this agreement is meant to be comprehensive, Tehran does not have the option of accepting a “freeze” in 2014 and then reviewing the deal in 2015 or 2016 to get the West to modify that ban.

Either Iran gives up its goal of self-sufficiency or the US and European allies make a leap of faith and accept some increase in Iranian capacity. There is no third way, however long the extension for talks.

Western officials